1. Field of the Invention
The present invention relates to a folder that cuts fed web into sheets and folds the sheets into signatures in accordance with selected folding specifications.
2. Description of the Related Art
FIG. 17 shows a conventional folder that cuts fed web into sheets and folds the sheets into signatures in accordance with selected folding specifications (as disclosed in, for example, Japanese Utility Model Publication (kokoku) No. H07-43097 and Japanese Patent Application Laid-Open (kokai) No. H06-1526).
As shown in FIG. 17, a pair of upper tension rollers 111a and 111b is disposed above a pair of lower tension rollers 112a and 112b. A cross perforating cylinder 113a for perforating printed web 1 in the width direction of the web 1, and a corresponding bearing cylinder 113b are disposed between the upper tension rollers 111a and 111b and the lower tension rollers 112a and 112b. 
A cut-off cylinder 121 having a cut-off knife and adapted to cut the printed web 1 in the width direction of the web 1 is disposed under the lower tension rollers 112a and 112b. The cut-off cylinder 121 is in contact with a folding cylinder 122. The folding cylinder 122 has pins and folding blades. The pins are adapted to hold a leading end portion of a sheet, which has been cut off from the web 1. The folding blades are adapted to fold the sheet along the width direction thereof at an arbitrary position. The folding cylinder 122 is in contact with a first jaw cylinder 123. The first jaw cylinder 123 has gripper boards and folding blades. The gripper boards are adapted to grip the folded portion of the sheet. The folding blades can be set in such a manner as to fold a signature 2, which has been formed as a result of the sheet being folded, at an arbitrary position along the width direction of the signature 2. The first jaw cylinder 123 is in contact with a second jaw cylinder 124, which has gripper boards for gripping the signature 2 at an arbitrary position.
In the vicinity of the second jaw cylinder 124 is disposed a conveyor apparatus 131 for conveying the signature 2 by means of conveyance belts 131b wound around and extending between rollers 131a. A fan wheel 132 is disposed downstream of the conveyor apparatus 131 with respect to the conveying direction of the conveyance belts 131b. A delivery conveyor 133 for delivering the signatures 2 is disposed under the fan wheel 132. In FIG. 17, reference numeral 134 denotes a chopper blade.
Next will be described the operation of the thus-configured conventional folder.
When the fed web 1 passes through between the cross perforating cylinder 113a and the bearing cylinder 113b via the upper tension rollers 111a and 111b, the cross perforating cylinder 113a perforates the web 1 across its width at predetermined longitudinal intervals. Subsequently, while the web 1 is passing through between the cut-off cylinder 121 and the folding cylinder 122 via the lower tension rollers 112a and 112b, the cut-off cylinder 121 cuts the web 1 at the predetermined longitudinal intervals into sheets. The sheets are held on the folding cylinder 122.
When the sheet held on the folding cylinder 122 is conveyed to the contact position where the folding cylinder 122 is in contact with the first jaw cylinder 123, the folding blade of the folding cylinder 122 and the gripper board of the first jaw cylinder 123 cooperatively perform gripping change on the sheet in such a manner that the sheet is folded at an arbitrary position and gripped by the first jaw cylinder 123. Thus, the sheet is held on the first jaw cylinder 123 in the form of the signature 2.
When the signature 2 held on the first jaw cylinder 123 is conveyed to the contact position where the first jaw cylinder 123 is in contact with the second jaw cylinder 124, and is to be folded further, the folding blade of the first jaw cylinder 123 and the gripper board of the second jaw cylinder 124 cooperatively perform gripping changes on the signature 2 in such a manner that the signature 2 is folded further and gripped by the second jaw cylinder 124. In the case where the signature 2 does not need to be folded further, the signature 2 merely undergoes a gripping change from the first jaw cylinder 123 to the second jaw cylinder 124 and is held on the second jaw cylinder 124. In this manner, the sheet is formed into the signature 2 of a parallel single-time folding (double folding), a parallel two-time holding (quarto folding), or a delta folding (triple folding).
The signature 2 held on the second jaw cylinder 124 is transferred to the conveyance belts 131b of the conveyor apparatus 131 and conveyed by the conveyor apparatus 131. The thus-conveyed signature 2 is delivered onto the delivery conveyor 133 via the fan wheel 132 and conveyed to the next step.
According to the conventional folder, for example, when the width of the web 1 is changed as a result of connection of the web 1 of a different width to the preceding web 1 or when folding specifications for the signature 2 are to be changed in the course of printing, the folder is halted before the web 1 of the different width enters the folder or before the folding specifications are changed. Then, an operator manually removes a piece of the web 1, sheets, and the signatures 2 from the interior of the folder and modifies settings of internal mechanisms, such as the conveyor apparatus 131, of the folder, in accordance with the new width of the web 1 or new folding specifications. Subsequently, the operator starts the folder to resume folding. Thus, work efficiency is very poor, and printing cost is increased.